A method is provided for separating off acid gases, in particular CO2 and H2S, from a hydrocarbon-rich fraction, in particular natural gas. The hydrocarbon-rich fraction is cooled and partially condensed. The resultant CO2-enriched liquid fraction is separated by rectification into a CO2-rich liquid fraction and a CO2-depleted gas fraction. The hydrocarbon-rich fraction is cooled close to the temperature of the CO2 triple point by means of a closed multistage refrigeration circuit. The refrigerant is a CO2 fraction of greater than 99.5% by volume. The rectification column is operated at a pressure between 40 and 65 bar. The reboiler of the rectification column is heated by means of a condensing refrigerant substream of the refrigeration circuit that is at a suitable pressure level.